Hybrid powertrains including one or more internal combustion engines and one or more motor/generators can be used to provide motive power to vehicles. Such hybrid powertrains offer the potential for multiple advantages including reduced fuel consumption, reduced pollution and emissions, and greater operational flexibility among others. The advantages of hybrid systems have been limited by the significantly more complicated to control and diagnostic problems which they present. Present approaches to controls and diagnostics for hybrid powertrains suffer from a number of drawbacks, limitations, disadvantages and problems. There is a need for the unique and inventive hybrid powertrain diagnostics and controls disclosed herein.